1. Field of the Invention
The present invention refers to a system for preventing the formation of electric arcs in connectors interspersed in an electric power distribution network, particularly applicable to a network assembled in an automotive vehicle for feeding power loads, such as a 42V network of a vehicle with two voltage levels (14V and 42V, or dual voltage system) for the purpose of preventing that, when the connector components are fortuitously or accidentally separated, or due to a lack of warning of a handler, an electric arc between contact points is generated which causes destruction or early deterioration of said contacts, or of the connector itself, an ill-timed interruption of the feed to certain loads of the network, or a fire situation with more or less severe damage, especially during the disconnection of the two electroinsulating parts or supports, components of a connector, bearing the electroconductive contact terminals.
The invention is also especially interesting for electric vehicles in which a set of batteries is used to provide power to an electric motor intended for driving the vehicle, and in which the current levels are in the range of 400 A at 400 V for DC, and 40 A at 220 V for AC, which current and voltage values require the incorporation of a series of safety measures for minimizing the risk of injuries to users, mechanics and safety technicians.
The invention also refers to a method for preventing the formation of electric arcs, as well as to a connector used in said system and method.
2. Description of the Invention
There are numerous documents which tackle the drawback of electric arc formation, both upon connecting as well as, especially, upon disconnecting the two component parts of a connector incorporated in a load feed network, at a voltage level susceptible to generating said electric arcs.
Patents EP-A-697751, EP-A-673085 and U.S. Pat. No. 6,146,160 disclose connectors with means for an effective mechanical clamping of the connection terminals, typically pins and electroconductive sockets, such that an accidental disconnection thereof cannot occur.
U.S. Pat. Nos. 3,945,699, 4,749,357 and 5,676,571 disclose means associated to the electroconductive pin receiver females, provided for obstructing or minimizing electric arc formation when connecting the two connector components.
U.S. Pat. No. B1-6,225,153 discloses a universal charge port connector for electric vehicles, in which a mechanism is provided for cutting off the current susceptible to generating an arc during disconnection of the male and female terminals of the connector before decoupling of the two component parts of said connector, particularly for preventing the disconnection of the connectors while charging vehicle batteries, which mechanism includes a mechanical lock of said two parts actuated by a lever which is associated to a switch coupled to a power source for the connector assembly, through which switch, and when the lever is actuated by a user, current circulation towards the power load to be fed is disabled before enabling the disconnection of the male-female power terminal or terminals of the connector.
U.S. Pat. No. 5,542,425 discloses an apparatus and method for preventing the deterioration of the contacts in electric equipment, specifically in image acquisition equipment with an ultrasound system in which several probes can be linked to the acquisition system with no risk of an electric arc being able to jump when disconnecting said probes, in which system the connector includes a mechanically actuated element for actuating and deactivating a connection interface between components, including a sensor or detector determining when the connector is going to be disconnected by one of the components, and provides a signal used by one of the components for disabling the electric power feed to the connector and thus preventing electric arc formation upon physically separating the male-female terminals thereof. In the different examples illustrated by this patent, said element is a rotating shaft which the user must act on, and said sensor is an optical sensor, magnetic sensor or simple switch.
In the last two background examples, the feed source disconnection is carried out either by the user (as in U.S. Pat. No. B1-6,225,153) or by means of the addition of a sensor associated to a mechanism likewise actuated by the user (as in U.S. Pat. No. 5,542,425), being necessary to always act on the connector with means for suitably moving its contacts, delay generation being essential for suitable functioning due to the mechanical actuation conditions.
Unlike said background, in the system, method and connector of the present invention, the connector itself includes passive means, such as additional terminals associated to an auxiliary circuit which, due to their configuration or position in the connector, constitute detection means susceptible to generating a signal indicating a situation prior to disconnection of the power terminals of the connector during the decoupling run thereof. From said signal, a disconnection protection device disables the electric power feed to the connector at hand before the physical separation of the power terminals occurs. The connector of the present invention is of a conventional structure, including two socket coupling electroinsulating blocks, generally of multiple contacts.
The system provides for an electronic unit susceptible to individually controlling a plurality of different connectors interspersed at different points of the network for electric current distribution towards the power loads.